Whether or not 36B is "bigger" depends entirely on the individual. Some 18-year-old Indian girls may wear a smaller size, some a larger size, and some a 36B. It's a perfectly normal and common size.
Key takeaway: Don't compare bra sizes based on age or ethnicity. Focus on finding the right fit for *your* measurements.
How to determine the correct bra size:
* Measure accurately: Use a measuring tape to measure both underbust and bust. You can find guides online on how to do this correctly.
* Try on different sizes and styles: Bra sizes can vary slightly between brands and styles. Trying on bras is the best way to find the perfect fit.
* Get professional help: If you're unsure, consider visiting a lingerie store or department store for a professional bra fitting.
Ultimately, comfort and support are the most important factors. The right bra size will feel comfortable and provide adequate support.